Enhanced low profile sockets and module systems

ABSTRACT

A socket system that comprises a printed circuit board; an electrical module; and a socket having a hollow core. The socket holds the electrical module and is capable of electrically coupling the electrical module to the printed circuit board. The electrical module has at least one electrical lead. The socket has at least one electrical lead capable of electrically coupling with the electrical lead(s) of the electrical module. The electrical module comprises a second printed circuit board having a first and second surface; a lithium battery positioned on the first surface of the second printed circuit board and electrically coupled with the second printed circuit board, a crystal positioned on the first surface of the second printed circuit board and electrically coupled with the second printed circuit board, and an integrated circuit positioned on the second surface of the second printed circuit board. A cap extends around and encloses and seals electrical elements of the electrical module. The cap may also have a baffle extending from the cap to surround and secure selected electrical components housed by the cap of the electrical module. The process of providing a printed circuit board, mounting a socket on the printed circuit board, placing the printed circuit board with the socket mounted on it in surface mount reflow oven and heating the printed circuit board and the socket to bond the socket to the printed circuit board, placing a cap over and around an electrical module and bending extended edges of the cap over and around the electrical module to seal electrical components inside the electrical module; and inserting an electrical module with the cap in the socket. If baffles are used, they will need to be aligned with selected electrical component of the electrical module.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of co-assigned, patentapplication entitled "Low Profile Sockets and Modules for SurfaceMountable Applications" that has U.S. Ser. No. 08/092,631, which wasfiled on Jul. 16, 1993 by Neil McLellan, Mike Strittmatter, Joe Hundt,and Christopher Sells (DSC-407), now U.S. Pat. No. 5,528,463.

This application hereby incorporates by reference the followingco-assigned issued patents and patent applications:

    ______________________________________                                              Patent Number                                                                              Issue Date/                                                DSC-# Ser. No.     Filing Date                                                                             Title                                            ______________________________________                                        69    5,050,113    09/17/91  Low Power                                                                     Timekeeping System                               70    4,959,646    09/25/90  Dynamic PLA Time                                                              Circuit                                          71    5,003,501    03/26/91  Precharge Circuitry                                                           and Bus for Low                                                               Power App'ns                                     72    4,873,665    10/10/89  Dual Storage Cell                                                             Memory                                           72A   542,689      06/25/90  Dual Port Static RAM                                                          with Bidirectional                                                            Shift Capability (as                                                          amended)                                         73    5,197,142    03/23/93  Memory Arbitration                                                            Between Timekeeping                                                           Circuitry and                                                                 General Purpose                                                               Computer (as                                                                  amended)                                         81    4,876,465    10/24/89  Dynamic CMOS Buffer                                                           for Low Current                                                               Switching                                        400   08/075,192   06/09/93  Thermal Protection                                                            of Electrical                                    407   08/092,631   07/16/93  Low Profile Sockets                                                           and Modules for                                                               Surface Mountable                                                             Applications                                     416   08/251,885   06/01/94  Enhanced Thermal                                                              Protection Systems                                                            and Methods                                      ______________________________________                                    

FIELD OF INVENTION

The present invention relates generally to systems of low profilesockets and modules that are compatible with existing surface mountablesystems, methods, and applications and, more particularly, but not byway of limitation, relates to unique sockets and unique modules thathave unique features that allow increased density and reduced profile.

BACKGROUND

Surface mount packaging technology has become a pronounced trend overthe past several years and has dramatically impacted modern packagingtechnology. In fact, this trend has become so pronounced that many boardassembly operations do not have wave solder capabilities (for use intraditional hole insertion processes) at all. Instead, these modernboard assembly operations have 100% of their production in the form ofsurface mount assembly.

The prevalence of surface mount packaging technology and the associatedadvantages have forced component manufacturers to redesign andreconfigure many products to make them compatible with existing surfacemount package families. This has poised unique problems for componentmanufacturers, especially for those manufactures that manufactureproducts that are sensitive to temperature (i.e., timekeepingcomponents).

SUMMARY OF THE INVENTIONS

The present invention provides low profile sockets and modules forsurface mountable applications. In particular, preferred embodiments ofthe socket/module system are comprised of a first printed circuit board,an electrical module, and a socket having a hollow core. The socket andmodule are low profile and compatible with existing surface mountingprocesses and structures. The socket holds an electrical module and iscapable of electrically coupling the electrical module to the firstprinted circuit board. The electrical module comprises a second printedcircuit board and a host of electrical elements electrically coupledwith the first printed circuit board. The electrical module has at leastone electrical lead and the socket has at least one electrical contactcapable of electrically coupling with the electrical lead(s) of theelectrical module. The electrical lead(s) of the electrical modulepreferably have a "F" clip lead design resembling "J" lead designscommonly used in plastic leaded chip carrier packages, which allows forgood insertion of the electrical module and retention of the electricalmodule by the socket. The electrical leads are, thus, coupled to theelectrical components inside the module via the second printed circuitboard. In addition, preferred embodiments have a fewer number of leads(e.g., half as much) than traditional embodiments.

The second printed circuit board in the module preferably has a firstand second surface. A lithium battery is positioned on the first surfaceof the second printed circuit board and electrically coupled with thesecond printed circuit board. A crystal is positioned on the firstsurface of the second printed circuit board and electrically coupledwith the second printed circuit board. An integrated circuit ispositioned on the second surface of the second printed circuit board.The printed circuit boards are thin and multilayered. The integratedcircuit in preferred embodiments is a clock circuit or a non-volatilestatic random access memory (NVSRAM) controller and static random accessmemory (SRAM). The first surface and the second surface are opposite oneanother.

A tub or cap encloses or caps the electrical module, which may include alithium battery and the crystal, and is comprised of injection moldedplastic. The walls of the tub or cap are thinned and curved to permit alow profile for the overall system. Components in the electrical moduleand, thus, the electrical module itself may be temperature sensitive.The socket is surface mountable and is compatible with surface mountableintegrated package sockets. The electrical contact(s) of the socket aremountable to the first printed circuit board (i.e., motherboard) usingsurface mount technology. Alternate preferred embodiments of the sockethave at least one interior wall with the electrical contacts(s) locatedon the interior wall(s). The second surface generally faces the secondprinted circuit board. Alternate preferred embodiments of the clockmodule position a lithium battery, a crystal, and a integrated circuitall on a first surface of a printed circuit board. The first surface andthe second surface are opposite one another. The second surface facesthe printed circuit board. The integrated circuit is sensitive totemperature and is typically a clock module or a NVSRAM controller andSRAM.

Preferred embodiments of the socket have a hollow body capable ofholding an electrical module and electrical contacts that are capable ofelectrically coupling the electrical module to a printed circuit board.The hollow body has a recess or hole in one end of the hollow body,which is shaped such that it accepts the electrical module. Theelectrical module has at least one electrical lead and the socket has atleast one electrical contact capable of electrically connecting to theelectrical lead(s) of the electrical element. The hollow body of thesocket is preferably comprised of poly phenelyne sulfide. One interiorsurface of the body of the socket has electrical contacts positionedthereon. Interior walls in alternate preferred embodiments have twointerior walls that face one another and have contacts positioned oneach interior wall. The electrical lead(s) of the body of the socket aremountable to the printed circuit board using surface mount technology.The electrical leads(s) of the socket have a "F" clip lead designresembling "J" lead designs commonly used in plastic leaded chip carrierpackages, which grip the contacts of the socket to provide a secureunit. A cap encloses the electrical module. Moreover, the shape of capis such that it can be easily grasped by robotic arms, which arecommonly used in modern manufacturing operations. The electrical moduleis temperature sensitive and/or may be comprised of a plurality ofelectrical components, some of which are temperature sensitive.Preferred embodiments of the socket are compatible with surfacemountable integrated package sockets.

Preferred embodiments have an extended lip, notch, or edge that whenheated to appropriate temperatures can be folded around the outer edgeof the printed circuit board in order to secure the cap in place as wellas to seal the electrical components inside. Caps having the formablelips are preferably comprised of formable plastics, such as liquidcrystal polymer. The electrical components, including the electricalcomponents, second printed circuit board, etc., in alternate preferredembodiments may also be partially encapsulated in or by the cap.Encapsulant (e.g., potting epoxy, such as that manufactured by AmiconCorporation) typically used provide mechanical support for all theelectrical components enclosed therein and help hold all the componentstogether. In addition, encapsulant provide a water tight (or degradingcleaning solvent), sealed overall assembly. This addresses concernsraised by standard manufacturing steps that remove cleaning flux fromthe populated board. In other words, encapsulating the resulting moduleprevents or minimizes water (or other degrading cleaning solvents) fromhaving ready access to the interior of the module, where it would shortthe battery and/or otherwise damage the components contained in themodule. Alternate preferred embodiments of the cap have at least one peg(but preferably a plurality of pegs positioned at opposite ends or oncorners) that is(are) inserted into the second printed board to securethe cap to the board in order to enclose electrical components therein(with or without the use of encapsulant). Caps or tubs may also have abaffle extending from internal surfaces of the cap or the tub to secureand help align electrical components of electrical modules, such as abattery. Adhesives can also be placed in and around the baffles tofurther seal the electrical components.

Preferred processes are comprised of the following steps: (a) providinga printed circuit board; (b) mounting a socket on the printed circuitboard; (c) placing the printed circuit board with the socket mounted onit in surface mount reflow oven and heating the printed circuit boardand the socket in order to bond the socket to the printed circuit board;(d) placing a cap over and around an electrical module and bendingextended edges of the cap over and around the electrical module to sealelectrical components inside said electrical module; and (e) insertingan electrical element in the socket. As a result, the electrical elementplaced in the socket avoids serious exposure to increased temperaturescommonly encountered in surface mount reflow ovens. The electricalmodule and socket have been specially designed to provide a low profileand increased density. Moreover, the electrical module and socket arecompatible with existing surface mount processes and systems andembodies the features described above. The printed circuit boardincludes a variety of other electrical components. The surface mountreflow oven heats the printed circuit board and the socket through oneof the means selected from the group consisting of convection, impingingradiation, and condensation. The electrical element is temperaturesensitive and typically a clock module or a Non-volatile Static RandomAccess Memory ("NVSRAM") controller and Static Random Access Memory("SRAM"). Preferred embodiments of the clock module comprises a secondprinted circuit board having a first and second surface; a lithiumbattery; a crystal; and an integrated circuit, wherein the lithiumbattery and the crystal are mounted on a first surface of the printedcircuit board and the integrated circuit is mounted on a second surfaceof the second printed circuit board. Alternate preferred embodiments ofthe clock module position a lithium battery, a crystal, and anintegrated circuit all on a first surface of a printed circuit board.The first surface and the second surface are opposite one another. Thesecond surface faces the printed circuit board. The integrated circuitis sensitive to temperature. Alternate preferred embodiments employ awater wash procedure, which cleans the first printed circuit board ofthe residue of water soluble flux before inserting the electricalmodule. The preferred procedures permit this additional step, whichcould otherwise damage (i.e., short out) the battery (i.e., lithiumbattery).

The disclosed invention has the following advantages. The socket/modulesystem and related processes can be used to install electricalcomponents (present in the electrical module) to printed circuit boardsusing surface mounting procedures without damaging the electricalcomponents that are temperature sensitive. The socket/module systems andrelated processes protect electrical components in the electrical modulefrom overheating. Examples of electrical components that are temperaturesensitive include temperature sensitive integrated circuits, lithiumbatteries, oscillator crystals, and non-volatile clock circuits. Thisability provides a host of additional advantages associated with surfacemount packaging technologies, such as the reduction of size, theincreased efficiency, the reduction of manufacturing cost, etc. Thesocket/module system and processes are relatively small in size and donot require an inordinate amount of space, especially when compared withmodules with similar functionality in traditional dual-in-line package("DIP") configurations. The disclosed socket/module system is smallenough to be compatible with generic surface mountable sockets. Inshort, the socket/module system and processes offer an unusually lowprofile (i.e., approximately 0.23" high) and increased density ofelectrical components, which is important with the increased emphasis onsize found in modern embodiments of personal computers (i.e., laptopsand notebooks). The socket/module system and related processes arecompatible with solder reflow assembly and compatible with off-the-shelfsurface mountable package sockets, which is significant because surfacemountable sockets are low cost and can be readily available. Inparticular, the socket/module system and related processes arecompatible with traditional waterwash processes. These waterwashprocesses generally remove a water soluble flux to clean the printedcircuit boards. The socket/module system and related processes are lightweight and require less surface area on the board. The printed circuitboard socket/module system and related processes offer reduced signalinterference and greater accuracy. Given the fact the electrical modulemay be bought and sold as a unit, the individual components can beinterconnected and calibrated more accurately than in processes andsystems that install the integrated circuit (i.e., clock circuitry)first without the lithium battery and crystal and then later add thelithium battery and the crystal to the electrical module after thereflow process and then calibrate the resulting system. Thesocket/module system and related processes can be easily calibrated. Thesocket system and related processes promote long battery life andreliability. The socket system and related processes permit easy andcorrect insertion into the socket/module system. Reducing the number ofleads reduces the cost of the socket (and module) as well as the cost ofthe resulting overall system. The holes in the socket help provide alower profile of the resulting overall system. Encapsulating the modulewith an encapsulant provides additional mechanical support for theelectrical components positioned therein and also create a water tight(or solvent tight) sealed assembly. Using alternate sealing mechanisms,such as the pegs and, especially, the extended lips that fold around thesecond printed circuit board reduce the overall material cost since theencapsulant are completely removed, reduce the mass of the overallfinished electrical assembly, reduce the manufacturing cycle time (sincethere are less steps), eliminates the possibility of getting epoxy onthe leads, removes concerns surrounding the free ion contamination fromepoxy. Using the baffle has the added advantage of aligning and sealingthe tub to electrical devices. In addition, if the adhesive is combinedwith the bottom of the baffle, the seal is further enhanced.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features and advantages will become apparent from the followingand more particular description of the various embodiments of theinvention, as illustrated in the accompanying drawings, wherein:

FIG. 1A is an illustration of a preferred embodiment of the low profilesocket/module system when the electrical module utilizes a chip-on-boardassembly without extra contact gaps;

FIG. 1B is an illustration of a preferred embodiment of the low profilesocket/module system when the electrical module utilizes a chip-on-boardassembly with extra contact gaps;

FIG. 2A and 2B illustrate relative differences in height for a 44 pinsocket with and without the relief hole respectively;

FIG. 3A and 3B illustrate relative differences in height for a 52 pinsocket with and without the relief hole respectively;

FIG. 4 is an illustration of a top view of the printed circuit board andassociated electrical components (i.e., the lithium battery, theintegrated circuit, and the crystal) shown in FIGS. 1A and 1B;

FIG. 5A is an illustration of the front view of the printed circuitboard and associated electrical components (i.e., the lithium battery,the integrated circuit, and the crystal) shown in FIGS. 1A and 1B;

FIG. 5B is an illustration of the side view of the printed circuit boardand associated electrical components (i.e., the lithium battery, theintegrated circuit and the crystal) shown in FIGS. 1A and 1B;

FIG. 6 is an illustration of the bottom view of the printed circuitboard and associated electrical components (i.e., the lithium battery,the integrated circuit, and the crystal) shown in FIGS. 1A and 1B; and

FIG. 7 is an illustration of a top view of the printed circuit board andassociated electrical components (i.e., the lithium battery, thecrystal, and the two integrated circuits, such as a static random accessmemory ("SRAM") and controller integrated circuit) in another preferredembodiment of the low profile socket/module system when the electricalmodule utilize a chip-on-board assembly with at least two integratedchips located on the printed circuit board of the chip-on-boardassembly, such as with nonvolatile SRAMs (SRAM and controller chip);

FIG. 8A is an illustration of the front view of the printed circuitboard and associated electrical components (i.e., the lithium battery,the crystal, and the two integrated circuits, such as a SRAM andcontroller integrated circuit) shown in FIG. 7;

FIG. 8B is an illustration of the side view of the printed circuit boardand associated electrical components (i.e., the lithium battery, thecrystal, and the two integrated circuits, such as a SRAM and controllerintegrated circuit) shown in FIG. 7;

FIG. 9 is an illustration of the bottom view of the printed circuitboard and associated electrical components (i.e., the lithium battery,the crystal, and the two integrated circuits, such as a SRAM andcontroller integrated circuit) shown in FIG. 7;

FIGS. 10A, 10B, 10C, and 10D are illustrations of the steps comprised ina preferred process to thermally protect electrical components;

FIG. 11 is an illustration of an alternate preferred embodiment of thelow profile socket/module system when the electrical module utilizes achip-on-board assembly with extra contact gaps and with the extended lipused to seal electrical components inside the electrical module;

FIGS. 12 and 13 illustrate relative module before placement into socketand after placement into socket;

FIG. 14 is an illustration of a top view of the printed circuit boardand associated electrical components (i.e., the lithium battery and thecrystal) shown in FIG. 11;

FIG. 15 is an illustration of the front or side view of the printedcircuit board and associated electrical components (i.e., the lithiumbattery and the crystal on one side and integrated circuit on the other)shown of the module shown in FIG. 11;

FIG. 16 is an illustration of the bottom view of the printed circuitboard and associated electrical components (i.e., the integratedcircuit) shown in FIG. 11; and

FIGS. 17A, 17B, and 17C are illustrations of cap or tub 213 by itselfwith baffle 215 extending from internal surfaces of cap or tub 213 tosecure electrical components of electrical modules, such as a battery.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1A is an illustration of a preferred embodiment of the low profilesocket/module system for surface mountable applications. The system isgenerally denoted by reference number 1. Electrical module is achip-on-board assembly generally denoted by reference number 3, whichcomprises in this embodiment a variety of electrical components: lithiumbattery 6 and crystal 8 on a first surface 7A of first printed circuitboard 7 and integrated circuit 15 (i.e., a clock circuit) on a secondsurface 7B of first printed circuit board 7, which is not apparent inFIGS. 1A and 1B (See FIG. 6). Electrical module could be or include avariety of other electrical elements, such as those shown in FIGS. 7-10.The chip-on-board ("COB") assembly provides a lower profile for theresulting structure, which minimizes its protrusion out of the socket10. All of the electrical components of electrical module 3 arepositioned proximate to one another. Please note that while FIG. 1Ashows lithium battery 6 and crystal 8 positioned on a first surface 7Aof first printed circuit board 7 and integrated circuit 15 on a secondsurface 7B that faces in an opposite direction of first printed circuitboard 7, other electrical elements could be positioned elsewhere oneither first surface 7A or second surface 7B or, perhaps, anothersurface. First printed circuit board 7 is preferably a thin(approximately 0.025" thick) multilayer design with "F" clips solderedto appropriate sides for connection to socket 10. In addition, epoxyglob material is used to seal and enclose integrated circuit 15 onsecond surface 7B.

First printed circuit board 7 has at least one component lead 4 (or atleast one conductive component pin 4) (please note that a plurality ofcomponent leads 4 is actually shown in FIGS. 1A and 1B). Integratedcircuits in preferred embodiments typically have 44, 52, or 68 componentleads 4 (see FIG. 2A and 2B), but integrated circuits in alternatepreferred embodiments may have as many as 8 component leads 4 or higher.First printed circuit board 7 inserts or snaps into socket 10, such thatplurality of component leads 4 electrically connect to the plurality ofsocket contacts 9 of socket 10. FIG. 1B is an illustration of apreferred embodiment of the low profile socket/module system for surfacemountable systems and methods with extra contact gaps 25 to house extrasocket contacts 9 of socket 10 (if needed). The embodiment shown in FIG.1B provides manufacturing flexibility. In particular, socket 10 can bestandardized for production purposes and yet still be customized toaccept and hold various electrical modules 3 with various sizes andrequirements (i.e., lead requirements). The requirements and uniquefeatures of second printed circuit board 19 (i.e., the position of otherelectrical components [not shown] that have certain electrical routingrequirements of buried electrically conductive interconnects withinsecond printed circuit board 19) may also dictate the position of socketcontacts 9 (of socket 10) and of component lead(s) 4 (of electricalmodule 3). Second printed circuit board 19 is larger than first printedcircuit board 7. Please note that corresponding items have been labeledconsistently between FIG. 1A and 1B.

Component lead(s) 4 are external and will be preferably soldered "F"clips designed to mimic "J" leads of plastic leaded chip carrier("PLCC") socket packages to firmly retain the electrical module(s). As aresult, the cross sectional profiles of the package resemble theprofiles of PLCC packages and, thus, are compatible with moretraditional PLCC sockets. Alternate embodiments are designed to becompatible with quad flat pack ("QFP") sockets. Preferred embodiments,however, have component lead(s) 4 on a minimal number of interiorsurfaces (i.e., one or two sides), which substantially reduces themanufacturing cost associated with the finished product as well as theoverall size. In addition, the reduction of the number of internalsurfaces of socket 10 and electrical module 3 containing socket contacts9 and component lead(s) 4 respectively reduces and simplifies therouting requirements of buried electrically conductive interconnectswithin second printed circuit board 19. In particular, the electricalconnections buried in the circuit board are straighter and otherwisemore manageable than in situations where the socket and module hascontacts and leads on more than two sides of socket 10.

Preferred embodiments of socket 10 are generally a surface mount PLCCcompatible designs. Socket 10 is hollow and has specially designed thinwalls (i.e., approximately 10 mils thick). Alternate preferredembodiments profile quad flat pack (QFP) designs. As noted, preferredembodiments also have leads on a minimal number of times (i.e., one ortwo sides). Preferred embodiments of socket 10 are generally comprisedof the following materials: nylon, thermal plastic (LCP), and polyphenelyne sulfide. In addition, the edges of socket 10 and/or electricalmodule 3 are chamfered to encourage and hopefully guarantee correctinsertion of electrical module 3 into socket 10. Preferred embodimentsfor socket 10 have a relief hole or recess 17 in the bottom surface ofsocket 10 which is positioned adjacent or on top of a second printedcircuit board 19 to allow electrical components to extend further intosocket 10. Additional relief holes or recess 17 can also be used toreduce manufacturing cost, increase density, and reduce the profile ofthe resulting system. However, the presence of the relief hole or recess17 located to accept electrical components positioned on the undersideof first printed circuit board 7 is especially important, because itallows electrical module 3 with first printed circuit board 7 andassociated electrical components to sink lower into socket 10 and,therefore, reduce the cross-sectional profile of the overall system 1(see FIGS. 2A, 2B, 3A, and 3B). Relief hole(s) or recess 17 arepreferably rectangular, but may assume other shapes as well.

Socket 10 is typically positioned on a second printed circuit board 19,which may contain a variety of other electrical components electricallyconnected or bonded to the larger printed circuit board, such asmicroprocessors and memory chips. Like first printed circuit board 7,second printed circuit board 19 is preferably a thin multilayer design.

FIGS. 2A and 2B illustrate relative differences in height for a 44 pinsocket 10 with electrical module 3 with and without the relief hole orrecess 17 respectively. In particular, as shown in FIG. 2B, a typical 44pin socket 10 is 0.900" square and has a height that approximates 0.255"(when the socket assembly is loaded upon the second printed circuitboard 19), whereas, as shown in FIG. 2A, a typical 44 pin socket 10 hasa height that approximates 0.222" (when the socket assembly is loadedupon the second printed circuit board 19). In particular, as shown inFIG. 3B, a typical 52 pin socket 10 is 1.000" square and has a heightthat approximates 0.285" (when the socket assembly is loaded upon thesecond printed circuit board 19), whereas, as shown in FIG. 3A, atypical 52 pin socket 10 has a height that approximates 0.252" (when thesocket assembly is loaded upon the second printed circuit board 19).Electrical module 3 is also of low mass to preclude fretting corrosion.

Tub or cap 13 is positioned over and around (encapsulates) lithiumbattery 6 and crystal 8 and over first printed circuit board 7 and isattached or affixed to first printed circuit board 7. Tub or cap 13 istypically filled with epoxy to secure it around the electricalcomponents to provide additional mechanical security, such as damagingthe components from handling or electrically shorting the components out(i.e., covering the anode and cathode of the battery), and additionalprotection for lithium battery 6. Tub or cap 13 is typically comprisedof injection molded plastic, nylon, thermal plastic, and liquid crystalpolymers ("LCP"). Tub or cap 13 has specially designed thin walls (i.e.,0.616") to maximize the density of components in the electrical module 3as well as in the overall system 1 in which the socket/module system isplaced. Tub or cap 13 is also chamfered to help visually orient tub orcap 13 with socket 10. Moreover, the shape of tub or cap 13 is such thatit can be easily grasped by robotic arms.

FIG. 4 is an illustration of a top view of electrical module 3 and someof the associated electrical components (i.e., first printed circuitboard 7, lithium battery 6, crystal 8) and component lead(s) 4 shown inFIG. 1.

FIG. 5A is an illustration of the front view of the first printedcircuit board 7 and associated electrical components (i.e., lithiumbattery 6, crystal 8, and integrated circuit 15) shown in FIGS. 1A and1B.

FIG. 5B is an illustration of the side view of the first printed circuitboard 7 and associated electrical components (i.e., lithium battery 6,crystal 8, and integrated circuit 15) shown in FIGS. 1A and 1B.

FIG. 6 is an illustration of the bottom view of the first printedcircuit board 7 and the integrated circuit 15 positioned on a secondsurface 7B of first printed circuit board 7 (i.e., underneath) that isopposite the first surface 7A of first printed circuit board 7 on whichlithium battery 6 and crystal 8 is shown in FIGS. 1A and 1B, but notshown in FIG. 6. Preferred embodiments may utilize a "glob" top, whichcovers, encloses, and protects integrated circuit 15. Please note,however, it has been removed in FIG. 6 in order to view integratedcircuit 15.

FIG. 7 is an illustration of a top view of first surface 7A of the firstprinted circuit board 7 and associated electrical components (i.e.,lithium battery 6, crystal 8, and integrated circuits 15 and 16, such asa SRAM and controller integrated circuit) in another preferredembodiment of the low profile socket/module system for surface mountableapplications. In particular, FIG. 7 shows electrical module 3 utilize aCOB assembly with at least two integrated chips located on the firstprinted circuit board 7 of the COB assembly integrated circuit 16 onfirst surface 7A of first printed circuit board 7 and integrated circuit15 on second surface 7B on first printed circuit board 7, such as withNVSRAMs, SRAM and controller chip. Please note that corresponding itemshave been labeled consistently between FIGS. 1A and 1B, except FIG. 7also illustrates the addition of an integrated circuit 16 on the firstsurface 7A of first printed circuit board 7.

FIG. 8A is an illustration of the front view of first printed circuitboard 7 and associated electrical components (i.e., lithium battery 6,crystal 8, and integrated circuits 15 and 16, such as an SRAM andcontroller integrated circuit) shown in FIG. 7.

FIG. 8B is an illustration of the side view of first printed circuitboard 7 and associated electrical components (i.e., lithium battery 6,crystal 8, and integrated circuits 15 and 16, such as an SRAM andcontroller integrated circuit) shown in FIG. 7.

FIG. 9 is an illustration of the bottom view of second surface 7B offirst printed circuit board 7 and associated electrical components(i.e., lithium battery 6, crystal 8, and integrated circuits 15 and 16,such as an SRAM and controller integrated circuit) shown in FIG. 7.Please note that FIGS. 7, 8A, 8B, and 9 show integrated circuit 15positioned on a second surface 7B (i.e., underneath) of first printedcircuit board 7 in a TSOP (e.g., thin small outline package) package aswell as integrated circuit 16 on a first surface 7A (i.e., on top) offirst printed circuit board 7 in a TSOP package, which is surfacemounted to first printed circuit board 7. Similar to the glob top, theTSOP package covers, encloses, and protects integrated circuit 15.

FIGS. 10A, 10B, 10C, and 10D illustrate the steps comprised in apreferred process to thermally protect electrical components. As shownin FIG. 10A, socket 10 is mounted on second printed circuit board 19.Second printed circuit board 19 may include a variety of otherelectrical parts 21. As shown in FIG. 10B, second printed circuit board19, which includes among other things socket 10, runs through surfacemount reflow oven, which heats second printed circuit board 19 throughconvection and impinging radiation (in the infrared spectrum) and/orthrough condensation (i.e., vapor phase) from above, as referenced byheat waves 11. As shown in FIG. 10C, electrical module 3 (containing theclock module, which is comprised of lithium battery 6, crystal 8, andintegrated circuit 15) is then inserted into socket 10. As shown in FIG.10C, electrical module 3 is then effectively positioned on secondprinted circuit board 19 and electrically connected via socket 10 tosecond printed circuit board 19, as shown in FIG. 10D. This processeffectively removes electrical module 3 from the reflow process in asurface mount reflow oven. This process would damage electrical module3, because the surfaces of electrical module 3 facing the surface mountreflow oven would typically absorb heat through convection and impingingradiation (in the infrared spectrum) and/or through condensation (i.e.,vapor phase) from above, as referenced by heat waves 11.

FIG. 11 is an illustration of an alternate preferred embodiment of thelow profile socket/module system for surface mountable applications whenthe electrical module 3 utilizes a COB assembly 3 with extended lip 150of alternate cap or tub 113 used to seal electrical components insidethe electrical module 120. Once again, when possible, the referencenumbers for identical elements have been carried forth to makeunderstanding the invention easier. While FIG. 11 does not show reliefhole or recess 17, which is shown in FIG. 1A, it may or may not beincluded in the alternate preferred embodiment shown in FIG. 11.Electrical module 120 is comprised a COB assembly, generally denoted byreference number 3 along with alternate cap or tub 113 with extended lip150. As mentioned above in reference to FIGS. 1A, 1B, 2A, 2B, 3A, and3B, electrical elements, including the electrical components themselves,second printed circuit board 19, etc., in preferred embodiments aregenerally encapsulated in or by the alternate cap or tub 113. Alternatetub or cap 113 is positioned over and around (encapsulates) lithiumbattery 6 and crystal 8 and over first printed circuit board 7 and isattached or affixed to first printed circuit board 7. While alternatetub or cap 113 can be filled with epoxy to secure it around theelectrical components to provide additional mechanical security and agood tight seal, as discussed above, alternate tub or cap 113 can alsobe sealed around electrical components using extended lip 150, whichwhen folded or heated bends around the edge of second printed circuitboard 19 next to, affixed to, and/or parallel to first surface 7A.Alternate tub or cap 13 is typically comprised of injection moldedplastic, nylon, thermal plastic, and liquid crystal polymers (LCP) thatbecomes pliable and formable when heated to appropriate temperatures,which are substantially less than temperatures commonly encountered intypical reflow processes (e.g., NOTE: WHAT EXACT RANGE??). Alternate tubor cap 13 has specially designed thin walls (i.e., 0.616") to maximizethe density of components in the electrical module 3 as well as in theoverall system in which the socket/module system is placed. Alternatetub or cap 13 is also chamfered to help visually orient alternate tub orcap 13 with socket 10. Moreover, the shape of alternate tub or cap 13 issuch that it can be easily grasped by robotic arms. It is important tonote that this alternate preferred embodiments is not exclusive orindependent from the alternate embodiments discussed above. In otherwords, these various sealing methods could be selectively combined withone another.

FIGS. 12 and 13 illustrate relative module before placement into socketand after placement into socket 10. Note the side view of socketcontacts 9 (as discussed above) or socket leads 140 before and aftersocket 10 with COB assembly 3 has been inserted in socket 10.

FIG. 14 is an illustration of a top view of electrical module 3 and someof the associated electrical components (i.e., first printed circuitboard 7, lithium battery 6, crystal 8) and component lead(s) 4 shown inFIG. 11.

FIG. 15 is an illustration of the front or side view of the printedcircuit board and associated electrical components (i.e., the lithiumbattery 6 and the crystal 8 on one side and integrated circuit on theother) shown of the electrical module 3 shown in FIG. 11.

FIG. 16 is an illustration of the bottom view of the printed circuitboard and associated electrical components (i.e., the integrated circuit15) shown in FIG. 11. Epoxy glob material 130 (see FIG. 16) is used toseal and enclose integrated circuits 15 on second surface 7B. Extendedlip 150 of alternate tub or cap 113 has been properly folded around theedge of second printed circuit board 117.

FIGS. 17A, 17B, and 17C are illustrations of cap or tub 213 by itselfwith baffle 215 extending from internal surfaces of cap or tub 213 tosecure electrical components of electrical modules, such as a battery.In addition, caps or tubs 213 may also have a baffle(s) 215 extendingfrom internal surfaces of the cap or tub 213 to secure electricalcomponents of electrical modules, such as a battery or crystal.Adhesives (e.g., NOTE: NAME THEM??) can also be placed in and aroundbaffles 215 to further seal the electrical components.

Note, if these alternate preferred embodiments having extended edges andbaffles are used, additional process steps may need to be added to theprocess shown in and discussed in reference to FIGS. 10A-10D. Inparticular, the steps should include bending extended edges of the capover and around the electrical module to seal electrical componentsinside said electrical module, aligning a baffle extending from said caparound a selected electrical component of said electrical module and/orapplying appropriate adhesives.

FURTHER MODIFICATIONS AND VARIATIONS

Although the invention has been described with reference to a specificembodiment, this description is not meant to be construed in a limitingsense. As described above, various modifications of the disclosedembodiment as well as alternate embodiments of the invention will becomeapparent to persons skilled in the art upon reference to the descriptionof the invention. Accordingly, it should be understood that themodifications and variations suggested above and below are not intendedto be exhaustive. These examples help show the scope of the inventiveconcepts, which are covered in the appended claims. The appended claimsare intended to cover these modifications and alternate embodiments.

What is claimed is:
 1. A socket system, comprising:(a) a printed circuitboard; (b) an electrical module; (c) a socket having a hollow core and arecess in one end of said socket, said socket holding said electricalmodule and electrically coupling said electrical module to said printedcircuit board; and (d) a cap having extended edges that bend around saidelectrical module to enclose and seal said electrical module.
 2. Thesocket system of claim 1, wherein said electrical module has at leastone electrical lead and said socket has at least one electrical leadcapable of electrically coupling with said electrical lead(s) of saidelectrical module.
 3. The socket system of claim 1, wherein saidelectrical module comprisesa second printed circuit board having a firstand second surface; a lithium battery positioned on said first surfaceof said second printed circuit board and electrically coupled with saidsecond printed circuit board; a crystal positioned on said first surfaceof said second printed circuit board and electrically coupled with saidsecond printed circuit board; and an integrated circuit positioned onsaid second surface of said second printed circuit board.
 4. The socketsystem of claim 3, wherein said integrated circuit is a clock circuit.5. The socket system of claim 3, wherein said first surface and saidsecond surface are opposite one another.
 6. The socket system of claim3, wherein a cap encloses said lithium battery and said crystal.
 7. Thesocket system of claim 6, wherein said cap is comprised of injectionmolded plastic.
 8. The socket system of claim 6, wherein said cap has aplurality of thin walls and a thin top to provide a low profile for saidsystem.
 9. The socket system of claim 1, wherein said recess is shapedto accept said electrical module when held by said socket, which createsa resulting profile of said socket and said electrical module together,said resulting profile reduced by said recess.
 10. The socket system ofclaim 1, wherein said electrical module is temperature sensitive. 11.The socket system of claim 1, wherein said electrical module comprises aplurality of electrical components, wherein some of said plurality ofelectrical components are sensitive to temperature.
 12. The socketsystem of claim 1, wherein said socket is surface mountable.
 13. Thesocket system of claim 1, wherein said socket is compatible with surfacemountable integrated package sockets.
 14. The socket system of claim 2,wherein said electrical lead(s) of said socket have a "F" clip leaddesign resembling "J" clip designs commonly used in plastic leaded chipcarrier socket packages.
 15. The socket system of claim 2, wherein saidelectrical lead(s) of said socket are mountable to said second printedcircuit board using surface mount technology.
 16. The socket system ofclaim 1, wherein said printed circuit board is thin and multilayered.17. The socket system of claim 2, wherein said socket has at least twointerior walls and said electrical lead(s) are located only on saidinterior walls.
 18. The socket system of claim 3, wherein said secondsurface faces said printed circuit board.
 19. The socket system of claim1, further wherein said cap has a baffle that secures an electricalcomponent of said electrical module in place.
 20. The socket system ofclaim 19, further wherein an adhesive is used to secure said cap to saidelectrical component and to seal said electrical component.
 21. A socketsystem, comprising:(a) a printed circuit board; (b) an electricalmodule; (c) a socket having a hollow core and a recess in one end ofsaid socket, said socket holding said electrical module and electricallycoupling said electrical module to said printed circuit board; and (d) acap having a baffle that secures an electrical component of saidelectrical module in place.
 22. The socket system of claim 21, furtherwherein an adhesive is used to secure said cap to said electricalcomponent and to seal said electrical component.